Screen

ABSTRACT

A projection screen includes a plurality of passive elements each having a sidewall surrounding a surface, wherein said sidewall is configured to attenuate light.

BACKGROUND

A popular class of display system is a front projection system. A frontprojection system projects an image onto a reflective screen whichdisplays the image. Front projection systems are generally suited forrelatively dark rooms because front projection screens indiscriminatelyreflect light incident to the surfaces with substantially equalefficiency. Light from the projector can be diluted by light from roomlights, windows, pixel-to-pixel interference, and/or other ambientlight.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate various embodiments of the presentapparatus and method and are a part of the specification. Theillustrated embodiments are merely examples of the present apparatus andmethod and do not limit the scope of the disclosure.

FIG. 1 illustrates a schematic view of an exemplary display system thatincludes an exemplary passive projection screen according to oneexemplary embodiment.

FIG. 2 illustrates an exemplary passive projection screen according toone exemplary embodiment.

FIG. 3A illustrates a partial cutaway side view of an exemplary passiveelement of a passive projection screen according to one exemplaryembodiment.

FIG. 3B illustrates a frontal view of an exemplary passive element of apassive projection screen according to one exemplary embodiment.

FIG. 4 illustrates a schematic view of an exemplary passive projectionscreen according to one exemplary embodiment.

FIG. 5 illustrates a schematic view of an exemplary display systemaccording to one exemplary embodiment.

FIG. 6 is a flowchart illustrating an exemplary method of forming apassive projection screen according to one exemplary embodiment.Throughout the drawings, identical reference numbers designate similar,but possibly not identical, elements.

DETAILED DESCRIPTION

An embodiment of a screen, such as a passive projection screen, isprovided herein that has a plurality of individual passive elementsformed thereon to enhance the contrast ratio of an image displayed inthe presence of ambient light. Further, the passive projection screenmay be formed of readily available materials using fabricationtechniques. These techniques may be used to adjust the performancecharacteristics of the passive projection display by varying thedimensions of the passive elements.

An embodiment of a display system will be described herein that makesuse of an exemplary passive projection screen. The passive projectionscreen will then be discussed, followed by a discussion of theconfiguration of individual passive elements, including passive elementsthat have angled sidewalls and passive elements that are configured tobe used with rear projection systems. Thereafter, an exemplary method offorming a passive projection screen will be discussed in more detail.

In the following description, for purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present method and apparatus. It will be apparent,however, to one skilled in the art, that the present method andapparatus may be practiced without these specific details. Reference inthe specification to “one embodiment” or “an embodiment” means that aparticular feature, structure, or characteristic described in connectionwith the embodiment is included in at least one embodiment. Theappearance of the phrase “in one embodiment” in various places in thespecification may possibly not be referring to the same embodiment.

Embodiment of a Display System Having a Passive Projection Screen

FIG. 1 illustrates an exemplary display system (100) according to oneexemplary embodiment. In particular, the display system (100) shown is afrontal projection system. The display system (100) generally includesan embodiment of a passive projection screen, such as passive projectionscreen (110), and an exemplary projector assembly, projector assembly(120). The projector assembly (120) described is exemplary only and maybe modified or changed as best serves a particular application.

Image data is input into an image processing unit (130). The image datadefines an image that is to be displayed by the projector assembly(120). While one image is illustrated and described as being processedby the image processing unit (130), it will be understood by one skilledin the art that a plurality or series of images may be processed by theimage processing unit (130). The image processing unit (130) performsvarious functions including controlling the illumination of a lightsource (140) and controlling a spatial light modulator (SLM) (150).

The light source (140) provides a beam of light to the spatial lightmodulator (150). The light source (140) may be, but is not limited to, ahigh pressure mercury lamp, a xenon bulb, or an array of light emittingdiodes.

The incident light may be modulated in its phase, intensity,polarization, or direction by the modulator (150). Thus, the SLM (150)of FIG. 1 modulates the light output by the projector assembly (120)based on input from the image processing unit (130) to form animage-bearing beam (160) that is eventually displayed or cast onto thepassive projection screen (110).

The image-bearing beam (160), as well as ambient light (170) from anambient light source (180), are both incident upon the passiveprojection screen (110). As will be discussed in more detail below, thepassive projection screen (110) directs a substantial portion of theimage-bearing beam (160) back toward a viewer (190) or viewers within aviewing cone, while attenuating the ambient light (170) directed backtoward a viewer (190) or viewers within a viewing cone. The attenuationof a portion of the ambient light (170) increases the contrast ratio ofthe image displayed on the passive projection screen (110). Theconfiguration of the passive projection screen (110) will now bediscussed in more detail.

Passive Projection Screen

FIG. 2 illustrates the passive projection screen (110) in more detail.The passive projection screen (110) includes a plurality of individualpassive elements (200) formed thereon to enhance the contrast ratio ofan image displayed in the presence of ambient light. As previouslydiscussed, the individual passive elements (200) direct light from adisplay system back toward a user while reducing the amount of lightfrom ambient sources that is directed back to the viewers.

The passive projection screen (110) is composed of a matrix ofindividual passive elements (200) in the form of hexagonal wells. Thematrix of hexagonal passive elements (200) forms a honeycomb pattern. Aswill be discussed in more detail below, the design of the passiveprojection screen (110) can be adjusted to vary the angle of view versusthe degree of rejection of ambient light. In particular, the height ofthe walls of each of the passive elements (200) may be increased toattenuate more light. As the height of the walls of the passive elementincreases, the size of the viewing cone decreases. Accordingly, theheight of the passive elements (200) may be adapted for the viewing coneto be used in any given application. The exemplary passive elements(200) discussed with reference to FIG. 2 are generally hexagonal inshape and may, according to one exemplary embodiment have a size ofapproximately 0.2 mm to about 1.0 mm or more with sidewalls havingaspect ratios (height divided by width) of about 10:1 or 20:1. Theelements may be of any suitable size and shape. For example, othershapes include, without limitation, squares, rectangles, and circles.

Further, the passive projection screen (110) can be tuned independentlyfor rejecting ambient light from the light sources located above orbelow the projection screen or for rejecting ambient light located tothe sides of the projection screen. The configuration of the passiveprojection screen (110) will now be discussed in more detail withreference to an individual passive element (200).

Configuration of Individual Passive Elements

FIGS. 3A-3B illustrates an individual element, such as a passiveelement, in more detail. In particular, FIG. 3A illustrates a cutawayside view of an individual passive element (200), while FIG. 3Billustrates a front view of the passive element (200). As shown in FIG.3A, the passive element (200) includes a front plane (300) and a rearplane or floor (310). A hexagonal well is formed in the front plane(300) such that the second or rear plane (310) forms a floor that issurrounded by sidewalls (320). The sidewalls (320) shown aresubstantially perpendicular (within the range of variation that mayresult from the technique used to fabricate the passive element) to boththe front and rear planes (300, 310). In one exemplary embodiment, thesidewalls (320) and the floors are each covered with matte white paintand treated to act as scattering reflectors.

Further, as shown in FIG. 3A, ambient light (170) from an ambient lightsource (180), such as a ceiling light fixture, that is incident on thepassive element (200) is far from normal with respect to the rear plane(310). Accordingly, the sidewalls (320) shade some of the rear plane(310) from this high-angle ambient light. Consequently, this ambientlight is not efficiently directed into the eyes of viewers.Alternatively, projected light from the image-bearing beam (160) arrivesnearly parallel to the sidewalls (320). The image-bearing beam (160) isthen reflected out of the passive element (200) and is relayed to theeyes of a viewer or audience. Accordingly, a substantial portion of theimage-bearing beam (160) is perceived by a viewer or audience while atleast some of the ambient light (170) is reflected away from the vieweror audience. The portion of incident ambient light (170) that isreflected away from the viewer or audience may be controlled by varyingthe dimensions of the passive elements, including the depth of thesidewalls (320).

Deeper sidewalls (320) increase the contrast ratio by reducing theamount of ambient light that reaches the viewer. However, there is atradeoff between the contrast ratio and the angle of view. Morespecifically, as the sidewalls (320) increase in depth, portions of theimage-bearing beam (170) are also attenuated from the viewer by thesidewalls (320). Consequently, the depth of the sidewalls (320) affects,at least in part, the contrast ratio and viewing angle of the passiveprojection screen (110).

In one exemplary embodiment, a passive projection screen (110; FIG. 1)includes a plurality of passive elements (200) each having dimensions ofapproximately 0.5 mm in depth by approximately 1.0 mm in width andheight. The base and sidewalls (320) of the exemplary embodiment weredeposited using three-dimensional printing techniques. In addition, thesurfaces of the sidewalls (320) and rear planes (310) were coated with amatte white paint.

The performance characteristics of the passive projection screen (110;FIG. 1) were then analyzed under controlled high ambient lightconditions and dark conditions and compared to the opticalcharacteristics of an 8½″×11″ size sheet of high-quality printer paperwhen receiving light from a typical digital projector. The results ofthe comparison are summarized below, in which the sensed light from thepassive projection screen are characterized by the designation “Hex” andthe sensed light from the sheet of paper is designated as “Paper.” Thepixels displayed are either white (W) or black (K) in order to calculatethe maximum contrast ratio (CR). Light coming off screen (cd/m²) toviewer centered in front of screen Fluorescent Lights On FluorescentLights Off Hex W 547 348 Hex K 195 0.52 Hex CR 2.8 669 Paper W 705 413Paper K 303 0.63 Paper CR 2.3 656

As shown above, with the ambient lights on, the passive projectionscreen attenuated the ambient light and increased the contrast ratiofrom 2.3 with a plain white surface to 2.8 with the passive projectionscreen. In the dark, where ambient light was substantially reduced, thestructure of the passive projection screen had very little effect on thecontrast ratio. Accordingly, the hexagonal structure of the individualpassive elements increases the contrast ratio of a displayed image.

As previously discussed, the dimensions of each of the passive elements(200) may be varied or adjusted to control the performancecharacteristics of the passive projection screen (110; FIG. 1). Inparticular, the width of the passive elements (200), which may bemeasured about a horizontal axis of the passive element, may beapproximately 200 μm or less. Further, the width and height of thepassive elements (200) may be independently varied to attenuate ambientlight from overhead light sources differently than light sources locatedto the sides of the passive projection screen (110; FIG. 1).

The exemplary projector screen (110; FIG. 1) discussed above includedpassive elements (200) having a single surface treatment applied theretoto reduce the amount of light that is directed back to the viewers. Theprojector screen (110; FIG. 1) may also be treated with multiple surfacetreatments. For example, the sidewalls (320) may be treated with a lightabsorbing surface treatment, such as gloss black paint, while the rearplane (310) may be treated with a diffuse reflecting surface, such asmatte white paint.

As previously discussed, light incident on such a screen comes from avariety of sources. For example, an incoming light ray that is nearlyperpendicular to the rear plane (310), may graze one of the sidewalls(320). The angle between such an incoming light ray and the sidewall(320) will be beyond a critical angle of the sidewall (320), and theincoming light ray will be substantially reflected by the sidewall(320). Thereafter, the incoming light ray will be incident on the rearplane (310), which then directs the light ray to the viewer.

In other cases, a light ray that arrives nearly perpendicularly to thesidewalls (320) will penetrate the light absorbing surface treatmentwhere the light is absorbed. By absorbing a portion of the ambient lightincident on each passive element, the passive projection screen (110;FIG. 1) further decreases the amount of ambient light directed back to aviewer, thereby increasing the contrast ratio of an image displayed inthe presence of ambient light.

The passive projection screens described thus far have made use ofsidewalls that are generally perpendicular to the rear plane or floors(310) of each of the passive elements. As shown in FIG. 4, a passiveprojection screen (110-1) may be formed having sidewalls (320-1) thatare tilted slightly. The size of the sidewalls (320-1) has beenexaggerated for ease of reference. The sidewalls (320-1) shown aretilted such that if each of the sidewalls were extended, they wouldconverge near a single point (not shown).

These sidewalls (320-1) may be formed using a photo imaging process,which may include a contact print process. In such a process, a layer ofSU8 epoxy is first deposited to form the front plane (300-1).Thereafter, a mask is formed that includes a field of black hexagonsseparated by thin clear lines. The thin clear lines correspond to theshape of the frontal view of the passive elements (320-1). This mask isplaced on the front plane (300-1), such as through contact printing.Thereafter, the front plane (300-1) with the mask applied thereto isexposed to light. Light passes through the thin clear lines while thedark black hexagons block the transmission of light. Light is thusselectively passed through the thin clear lines to the SU8 material. Aslight passes through the layer of material, it exposes the SU8 epoxy.This exposed material is then consolidated in a post exposure bakingstep, which causes molecular cross linking of the exposed SU8 epoxy.Thereafter, the unconsolidated material, which is the material below themask that has not been exposed, is removed leaving the consolidatedmaterial of the sidewalls (320-1). Accordingly, the material that isexposed and later consolidated to form the sidewalls depends, at leastin part, on how light is directed to the mask.

The light used in exposing the layer of SU8 epoxy may be provided by asingle point source. The light passing through the layers of SU8 wouldbe parallel to rays of light drawn from the point source, therebyexposing the material in the tilted fashion shown in FIG. 4. Aspreviously discussed, this exposed material is later consolidated toform solid walls, after which the non-exposed material is removed. As aresult, the sidewalls (320-1) of passive elements nearest the pointsource would have nearly perpendicular walls, while other passiveelements would have tilted walls. Accordingly, the sidewalls would betilted or biased toward a single point. The resulting passive projectionscreen (110-1) may focus light from the area of a single source, therebyreducing the amount of ambient directed to the viewer. Accordingly, thedimensions of the passive elements may be varied to control severalperformance characteristics.

Further, the passive elements may be adapted for use with rearprojection display systems. For example, as shown in FIG. 5, anembodiment of a rear projection display system (500) includes a passiveprojection screen (110-2) configured to be used with a rear projectionassembly (510). In such a configuration, the rear plane (310; FIG. 3) ofeach of the passive elements (300; FIG. 3) is formed of a transparentmaterial. As a result, light from the rear projection assembly (400) isable to pass through the passive projection screen (110-2) to be viewedby a viewer (190) or viewers. Further, the sidewalls (320; FIG. 3) ofeach of the passive elements (300; FIG. 3) shields a portion of the rearplane (310; FIG. 3) as previously discussed, thereby increasing thecontrast ratio of the image.

Accordingly, the passive projection screen attenuate ambient light tothereby increase the contrast ratio of an image displayed thereon. Inaddition, as will now be discussed in more detail, passive projectionscreens may be readily formed. Further, the size of the viewing angle,as well as the horizontal and vertical ambient light dissipatingproperties of the passive projection screens may be readily adjusted byvarying the dimensions of the passive elements.

Method of Forming a Passive Projection Screen

FIG. 6 is a flowchart illustrating an exemplary method of forming apassive projection screen. As previously introduced, the performancecharacteristics of the passive projection screen may be adjusted to suitenvironmental conditions by varying the dimensions of the passiveelements. Accordingly, the exemplary method begins by determining theambient conditions (step 600). These ambient conditions may includedetermining the likely location of ambient light sources and the desiredviewing angle of the passive projection screen. For example, ambientlight sources are frequently located overhead, such as in ceiling lightfixtures. In other situations, light sources may be located primarily tothe sides of the passive projection screens, such as may be the casewhere table lamps or wall lamps are used extensively. Further, someapplications allow the use of a relatively narrow viewing angle, such aswhen the display system is located in a long, narrow room. Otherfactors, which include without limitation, the geometry of theprojector, the geometry of the screen, and the characteristics of theaudience may also be used in determining the dimensions of the passiveelements.

These ambient conditions are then used to determine the dimensions ofthe passive elements (step 610). For example, where a higher contrastratio is desired, the depth of the passive elements may be relativelylarge. Further, in the case where ambient light is provided primarily byoverhead ambient light sources, the passive elements may be elongatedalong a horizontal axis. Similarly, where ambient light is providedprimarily by ambient light sources located to the side of the projectionscreen, the passive elements may be elongated along a vertical axis.

The passive elements are formed on a substrate (step 620). The substratemay be any suitable material, including materials commonly used informing projection screens. The passive elements themselves may beformed of any suitable material, including, without limitation, SU8epoxy resin. Several approaches may be used to form the passive elementsthat include, without limitation, etching, micro-embossing, orthree-dimensional printing.

Once the passive elements have been formed on the substrate (step 620),the surfaces are coated with at least one surface treatment (step 630).As previously discussed, the surfaces may be covered with a singlesurface treatment, such as matte white paint, to form surfaces which arescattering reflectors. These coatings may be applied by any suitablemeans including, without limitation, contact printing. Further, thesurfaces may be treated with multiple surface treatments, such astreating the surfaces of the sidewalls with a light absorbing surfacetreatment while treating the floors or rear planes of each of thepassive elements with a reflective material. Further, the rear planes ofeach of the passive elements may be formed with a transparent substrate.

In addition, the surfaces may be treated with screen gain enhancements(step 640) such as mica or glass beads that are applied to the surfacesof the passive projection screen. These particles increase the amount oflight reflecting off the rear plane of the passive projection screen andback to the viewer.

Accordingly, the present method provides for the formation of a varietyof passive projection screens. Formation of such passive projectionscreens by the disclosed techniques reduces the costs associated withproduction. Further, the present method provides for the formation ofpassive projection screens with characteristics that are well suited tothe operating environment of the display system.

The preceding description has been presented only to illustrate anddescribe the present method and apparatus. It is not intended to beexhaustive or to limit the disclosure to any precise form disclosed.Many modifications and variations are possible in light of the aboveteaching. It is intended that the scope of the claimed subject matter bedefined by the following claims.

1. A projection screen, comprising: a plurality of passive elements eachhaving a sidewall surrounding a surface, wherein said sidewall isconfigured to attenuate light.
 2. The projection screen of claim 1,wherein each of said sidewall form generally hexagonal shape.
 3. Theprojection screen of claim 2, wherein said general hexagonal passiveelements are elongated along a horizontal axis.
 4. The projection screenof claim 2, wherein said general hexagonal passive elements areelongated along a vertical axis.
 5. The projection screen of claim 2,wherein said plurality of general hexagonal passive elements form ahoneycomb type pattern.
 6. The projection screen of claim 1, and furthercomprising at least one surface treatment applied to said passiveelements.
 7. The projection screen of claim 6, wherein said surfacetreatment comprises matte white paint.
 8. The projection screen of claim1, and further comprising a plurality of surface treatments.
 9. Theprojection screen of claim 8, wherein said plurality of surfacetreatments comprises a light absorbing surface treatment applied to saidsidewalls and a reflective treatment applied to said surface.
 10. Theprojection screen of claim 1, and further comprising a scatteringreflective surface formed on said passive elements.
 11. The projectionscreen of claim 1, and further comprising a screen gain enhancementapplied to said passive elements
 12. The projection screen of claim 11,wherein said screen gain enhancement comprises mica.
 13. The projectionscreen of claim 11, wherein said screen gain enhancement comprises glassbeads.
 14. The projection screen of claim 1, wherein said surfacecomprise a transparent material.
 15. The projection screen of claim 1,wherein said sidewalls are tilted such that extensions of said sidewallsconverge near a single area.
 16. A projection screen, comprising: asubstrate having a first surface and a second surface; a plurality ofwells defined in said substrate to form a plurality of sidewallsextending between said first surface and said second surface, saidsidewalls surrounding a floor.
 17. The projection screen of claim 16,wherein said sidewalls are substantially perpendicular to said first andsecond planes.
 18. The projection screen of claim 16, wherein saidsidewalls are elongated along a horizontal axis.
 19. The projectionscreen of claim 16, wherein said sidewalls are elongated along avertical axis.
 20. The projection screen of claim 16, wherein said floorcomprise a generally transparent material.
 21. The projection screen ofclaim 16, wherein a plurality of said sidewalls are tilted with respectto said second plane.
 22. The projection screen of claim 21, whereinsaid sidewalls are oriented such that extensions of said sidewallconverge near a single area.
 23. The projection screen of claim 16,wherein said sidewalls have an aspect ratio in the range from about 10:1to about 20:1.
 24. The projection screen of claim 16, wherein saidsidewalls form a plurality of generally hexagonal elements.
 25. Theprojection screen of claim 16, wherein said sidewalls form a pluralityof generally square elements.
 26. The projection screen of claim 16,wherein said sidewalls form a plurality of generally rectangularelements.
 27. The projection screen of claim 16, wherein said sidewallsfor a plurality of generally circular elements.
 28. A method of forminga projection screen, comprising: forming a plurality of passive elementson a substrate, each element including a sidewall and a floor, saidsidewalls being configured to attenuate light.
 29. The method of claim28, and further comprising forming a scattering reflective surface oneach surface of said passive elements.
 30. The method of claim 28, andfurther comprising: determining ambient conditions in which saidprojection screen is to be operated; and establishing dimensions of saidhexagonal passive elements based on said ambient conditions.
 31. Themethod of claim 30, wherein determining said ambient conditions includesdetermining a location for at least one ambient light source.
 32. Themethod of claim 31, wherein establishing said dimensions compriseselongating said hexagonal passive elements with respect to a horizontalaxis.
 33. The method of claim 31, wherein establishing said dimensionscomprises elongating said hexagonal passive elements with respect to avertical axis.
 34. The method of claim 30, wherein determining saidambient conditions includes determining a viewing angle for saidprojection screen.
 35. The method of claim 30, wherein establishing saiddimensions includes establishing a depth of said sidewalls.
 36. Themethod of claim 28, wherein forming said passive elements comprisesdepositing a layer of material on said substrate, depositing a mask onsaid layer of material, exposing said mask to light from a single pointsource to form exposed sidewalls, and heating said layer of material tocause said exposed sidewalls to consolidate said exposed sidewalls, andremoving unconsolidated material from said layer of material such thatextensions of said sidewalls are substantially parallel to light rightsfrom said single point source.
 37. The method of claim 28, and furthercomprising applying at least one surface treatment to said passiveelements.
 38. The method of claim 37, wherein applying said surfacetreatment comprises applying matte white paint.
 39. The method of claim28, and further comprising applying a plurality of surface treatments tosaid passive elements.
 40. The method of claim 28, wherein applying saidplurality of surface treatments comprises applying a reflective surfacetreatment to said floors and a light absorbing surface treatment to saidsidewalls.
 41. The method of claim 28, and further comprising providinga screen gain enhancement on surfaces of said passive elements.
 42. Themethod of claim 41, wherein said screen gain enhancement comprises mica.43. The method of claim 41 wherein said screen gain enhancementcomprises glass beads.
 44. The method claim 28, wherein forming saidpassive elements comprises three-dimensional printing.
 45. The method ofclaim 28, wherein forming said passive elements comprises etching. 46.The method of claim 28, wherein forming said passive elements comprisesmicro-embossing.
 47. The method of claim 28, wherein forming saidpassive elements comprises depositing a light sensitive material,forming a mask on said light sensitive material, exposing said lightsensitive material to light to form exposed and unexposed portions,consolidating said exposed portions, and removing said unexposedportions.
 48. The method of claim 47, wherein depositing said lightsensitive material includes depositing SU8 epoxy.
 49. The method ofclaim 28, wherein forming said passive elements comprises forminggenerally hexagonal passive elements.
 50. The method of claim 28,wherein forming said passive elements comprises forming generallyrectangular passive elements.
 51. The method of claim 28, whereinforming said passive elements comprises forming generally square passiveelements.
 52. The method of claim 28, wherein forming said passiveelements comprises forming generally circular passive elements.
 53. Aprojection screen, comprising: a plurality of means for reflecting animage-bearing beam; and a plurality of means for attenuating ambientlight with respect to said reflecting means wherein said reflectingmeans are at least partially surrounded by said attenuating means. 54.The projection screen of claim 53, and further comprising means forscreen gain enhancement for enhancing a gain of said passive projectionscreen.
 55. A display system, comprising: a projection screen includinga plurality of passive elements each having a sidewall surrounding asurface, wherein said sidewall is configured to attenuate light; and aprojector configured to display an image on said projection screen. 56.The system of claim 55, wherein said projector comprises a frontprojection projector.
 57. The system of claim 55, wherein said projectorcomprises a rear projector.
 58. A projection screen formed by theprocess of: forming a plurality of sidewalls surrounding a surface bydepositing a layer of light sensitive material; forming a mask of shapesseparated by clear portions on said layer of light sensitive material;exposing said light sensitive material to light through said clearportions to form exposed portions and unexposed portions; consolidatingsaid exposed portions; and selectively removing said unexposed portions.59. The projection screen of claim 58, wherein depositing said lightsensitive material comprises depositing SU8 epoxy.
 60. The projectionscreen of claim 58, wherein forming said mask comprises contactprinting.
 61. The projection screen of claim 58, wherein exposing saidlight sensitive material to light comprises exposing said lightsensitive material to a single source of light.
 62. A projection screen,formed by the process of: forming a plurality of passive elements on asubstrate and a floor, wherein each element includes a sidewallconfigured to attenuate light.
 63. The projection screen of claim 62,wherein forming said passive element comprises forming a plurality ofgenerally hexagonal elements.
 64. The projection screen of claim 62,wherein said sidewalls have an aspect ratio of between about 10:1 toabout 20:1.
 65. The projection screen of claim 62, wherein saidsidewalls have a width of between about 0.2 mm to about 1.0 mm.